In the discussion that follows, reference is made to certain structures and/or methods. However, the following references should not be construed as an admission that these structures and/or methods constitute prior art. Applicant expressly reserves the right to demonstrate that such structures and/or methods do not qualify as prior art against the present invention.
Milling tools for hobbing are often provided as integral tools wherein the milling inserts are placed along a helical line along a cylindrical tool body. In the manufacture of such tools, there may occasionally be problems of gaining access to machine seats for the milling inserts or the milling inserts themselves in those cases they are integrated in the tool body. This depends on the fact that it occasionally is narrow between axially consecutive revolutions of the helical line of milling inserts. This is a reason for milling tools for hobbing also being provided in the form of tools wherein the cylindrical tool body is composed of a plurality of disc-shaped segments, each segment usually embracing one turn of milling inserts in the helical line.
A plurality of different such embodiments of segment hobs are previously known. In DE 10 2005 029053 A1, a segment hob is disclosed that comprises a cylindrical tool body, which is composed of a plurality of separate segments. The separate segments are rotationally secured in relation to each other by means of loose, separate fitting bolts. In each end, there is an end piece, and the entire package of segments and end pieces is kept together by long, through screws.
A problem of this previously known segment hob is that the machining precision of the generated surfaces in the workpiece does not become sufficiently high for certain applications. Furthermore, it is occasionally a problem to mount the separate segments on a common shaft or mandrel and occasionally intricate adjusting grindings are required. In such cases, it is particularly cumbersome if the tool, e.g., after an occurred damage to some individual segment, needs to be dismounted and again be put together with a new, undamaged segment.